ALBANY — Keith Bulluck speaks openly about a horrific childhood that would have broken and scarred a much weaker child.

He never knew his father. His mother abused alcohol. Her boyfriends, one of whom was his stepfather, abused her. And little Keith Bulluck was too often alone — sometimes for two days at a time — and virtually helpless.

“You know your mom’s getting her (butt) whupped, you know what I’m saying?” the veteran the Giants have tabbed to replace Antonio Pierce at middle linebacker was saying yesterday. “Sometimes I would try and interfere, but what can you do?”

He bounced around Rockland County, living with his grandmother in West Haverstraw, with his two older brothers in Spring Valley. Then his stepfather moved the boy to Nyack, where he befriended a classmate named Danny Welch, and his mother, Linda. Then his stepfather died, and a courageous boy’s life thankfully changed inside a New City foster home.

“I was supposed to stay there for two weeks, and two weeks turned into six years,” Bulluck said. “Linda Welch, she wanted to do the responsible thing and . . . didn’t know what to do, really. I guess then that’s when Child Protective Services came in and she did what she had to do to become my legal guardian, and the rest is history.

“Foster care gave me a chance to be a 12-year-old kid. A lot of times I took care of myself growing up a lot. I had companions my age. Miss Welch worked a lot, sometimes she worked two jobs, we all kinda looked after one another. The neighborhood kinda revolved around our house. Maybe that’s because Miss Welch wasn’t home until later at night (laugh).”

Bulluck became a free safety/running back at Clarkstown North HS. “I looked at myself as the next Ronnie Lott,” he said.

But the NFL was on the backburner.

“My first thing was to figure out what I’m gonna do at 18 when I age out of foster care because at 12 years old I had to make a decision: Did I want to be adopted or did I want to stay in foster care ‘til I was 21 or 18?” Bulluck said. “So at 12, I made a decision that at 18 I’m gonna be on my own and I’m gonna be out of foster care.”

He excelled at Syracuse and was drafted by the Titans late in the first round of the 2000 draft.

“I kinda was wishing and hoping that I would get picked up by one of the home teams,” Bulluck said.

But not for long. The late Steve McNair became a big brother for him.

“I got to learn how to become a professional from professionals,” Bulluck said.

He will soon emerge as one of Big Blue’s leaders.

“I’ve always been a leader,” Bulluck says. “I never need a ‘C’ on my chest to be a leader. You don’t have to be a captain of a team to be a leader. . . . If you’re a leader, you need to be more accountable than anyone else.”

Ask him what he’s like on the field and you can almost hear Lawrence Taylor howl with delight.

“I always said the person that I am on the field I cannot be in real life,” Bulluck said. “The person that I am on the field would have a hard time just walking the streets as a civilian.”

Bulluck needed a team after surgery seven months ago on his left ACL. The Giants needed a middle linebacker. He doesn’t think anymore about the knee. The Giants don’t doubt he can make the transition from the outside, where six times he compiled 100-plus tackles. Neither does he.

“For Coach Coughlin and his staff to give me this opportunity, I’m gonna run through the wall for this team,” Bulluck said.

Doubt him at your own risk.

“I like proving people wrong, because people can’t look and see what’s inside anyone’s heart,” Bulluck said.

He is 33 years old now, a father of two daughters.

“All I can do is just know that I’m gonna do better for my kids,” Bulluck said. “I know the things that I am not gonna do within my life.”

His left forearm bears this tattoo: Focus Plus Determination Equals Success. He named his foundation to aid foster children Believe And Achieve.